Connector for providing a humidity-tight electrical connection

ABSTRACT

A plug connector to produce a moisture-proof electrical coupling between a massive connecting wire and an electrical contact or contact element is generally composed of a receiving and guiding bush which has an inside diameter that is conformed to the outside diameter of the connecting wire and ends into an extension, and of a retaining element into which the wire tip is slipped when the wire is passed through the bush and through a pierceable foil. A permanently elastic sticky sealing compound is filled into the extension on the exit side of the bush. 
     In a variation, the receiving and guiding bush is closed on the exit side by a pierceable diaphragm.

The present invention generally relates to electrical connectors andmore particularly relates to a plug connector to produce amoisture-proof electrical coupling between a massive connecting wire andan electrical contact or contact element.

BACKGROUND OF THE INVENTION

Many different applications are possible for plug connectors of thistype. One application, which is in the center of interest in the presentexample, is the assembly and installation of electrically operatedcomponents and structural groups, electric circuits, printed circuitboards, or like elements, in automotive vehicle electronics. This fieldespecially focuses on reliability, mechanical and electrical loadingcapacity, on the one hand, and favorable manufacturing and assemblingcosts, on the other hand. Another requirement in vehicles and vehiclecomponents involves extensive protection against, or insensitivity to,humidity and contaminants.

Generally, the electrically operated or electrically connectedcomponents in an automotive vehicle are connected by way of cables andplug connectors, i.e., plugs and receiving bushes, and like elements.Frequently, costly manufacturing and assembling techniques are used toachieve sufficient sealing against moisture and contaminants, which isof critical importance for the reliability and long service life of thesystems. In addition, it is required in the majority of cases thatdetachment and reestablishment of the connection for maintenance, errordetection purposes and similar operations be possible at least severaltimes.

An object of the present invention is to provide a plug connector whichis appropriate for such applications, which can be detached andrecoupled at least several times, which withstands moisture andcontaminants, and which is reliable and adapted to be stressedmechanically and electrically. Another objective of the plug connectoris to minimize efforts in manufacture and assembly.

The connector of the present invention has a receiving and guiding bushwhich accommodates the connecting wire and ends into an extensionprovided for being filled with a permanently elastic sticky sealingcompound and used as a reservoir for the sealing compound, and includesa retaining element into which the wire tip, when inserted into thebush, penetrates through a previously closed foil or a thin wall of anyacceptable material.

In this way, a small number of simple and inexpensive components may beused to configure the plug connector, permitting quick asssembly andeffective sealing of the point of transition in relation to humidity andcontaminants. When the connecting wire is detached and withdrawn fromthe bush, the point of transition, or the site where the wire passesthrough, is closed and sealed by the permanently elastic sticky sealingcompound. Thus, the point of connection remains sealed until theconnecting wire is plugged in again.

In a favorable embodiment of the present invention, the retainingelement has the shape of a plug clamp, a soldering bush, or a likeelement which establishes the electrical contact between connecting wireand the contact element. An appropriate plug clamp of this type isdescribed in the patent application No. 196 15 706.4 (P 8683) which isnot yet published.

The connecting wire is preferably insulated, i.e., with an insulatingcasing which encompasses the metal wire, and extends through thecorrespondingly dimensioned bush, the extension and the pierceable foilup to the retaining element in which the insulated tip of the wire isinserted. At the transition to the extension, the bush may be providedwith a ‘stripping funnel’ or a like device.

The plug connector according to the present invention is especiallyappropriate for connecting a device to a printed circuit board which ismounted on a flat-surface cooling element (generally an aluminum orcopper plate), such that the bush is seated on the side of the coolingelement and the retaining element on the side of the printed circuitboard, and wherein the connecting wire is passed through correspondingapertures in the cooling plate and in the printed circuit board.

Further, the bush may terminate in an extension that is configured as arecess on the exit side of the bush and is filled with the sealingcompound through a separate feed opening or a feed channel. However, itis also possible to pour in the sealing compound through the bush intothe extension.

It is possible in all of the previous embodiments that upon insertion ofthe connecting wire into the bush or into the plug connector, thesealing compound which is thereby displaced is taken up by the extensionused as a reservoir. When the wire is withdrawn from the bush, at leastpart of the sealing compound is again drawn into the opening that isreleased, and closes the orifice.

In a variation of the plug connector of the present invention which isadvantageous or deemed at least sufficient in many cases, the receivingand guiding bush is closed by a pierceable diaphragm on the exit side ofthe plugged-in connecting wire. When the highly fluid sealing compoundis poured in, this compound will collect in the area of the diaphragmand in the adjacent extension. When the connecting wire is inserted andpunctures the diaphragm, the elastic sealing compound will seal theorifice area.

Further details and advantages of the plug connector of the presentinvention can be taken from the following description of embodimentsmaking reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-sectional and schematically simplifiedview of components of a plug connector of the type of the presentinvention and arrangement thereof on the cooling element and the bottomplate of the printed circuit board of an electronic controller.

FIG. 2 is a schematic view of a controller or a complete unit using theplug connector according to FIG. 1.

FIG. 3 is a schematic view of the design and the filling of a receivingand guiding bush for a design variation of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the most important components of a plug connector of thepresent invention before the insertion of a connecting wire 1. Wire 1 inthe FIG. 1 embodiment is used for contacting, or for establishing anelectrically conductive connection between a devia (not shown) to whichthe connecting wire 1 is fitted in a conventional manner (or by anotherplug connector of the type of the present invention) and the componentsor conductor paths on a bottom plate 2 which is part of a printedcircuit board 3 of an electronic controller. The entire printed circuitboard, which is shown in cross-section in FIG. 1, includes aflat-surface cooling element 4, (for) example, an aluminum plate,) andthe bottom plate 2 on which electrical, symbolically representedconstruction elements 5, 6 (transistors, capacitors, etc.) are mounted,and conductor paths (not shown). The bottom plate 2 and cooling element4 are interconnected by a thin adhesive foil 7 which has several layers,if necessary.

The connecting wire 1 is slipped into a receiving and guiding bush 8 ofthe plug connector of the present invention during an assembling ormanufacturing process. The wire 1 provided with an insulating casing 9is passed through the bush 8, extends through a free space or anextension 10 and through the adhesive foil 7, which is pierced by thewire 1, into a retaining element 11 which is herein configured as arepresented plug clamp. Plug clamp 11 receives only the uninsulatedfront part, i.e., tip 24 of the connecting wire 1. Openings 12, 13 areprovided in the cooling element 4 that correspond to openings in thebottom plate 2. The connecting wire 1 extends through the openings intothe plug clamp 11.

In the embodiment of the present invention according to FIG. 1, at thetransition from the bush 8 to the extension 10, there is a constriction23 in the shape of an elastic lip or a corresponding diaphragm partwhich, for example, provides a ‘stripping funnel’ or the like andthereby promotes closing and sealing the orifice after the plugconnector has been detached.

The free space or the extension 10 which is provided for being filledwith a permanently elastic sticky sealing compound is particularlyimportant for the function of the plug connector according to thepresent invention. Such sealing compounds, for example, bearing theproduct name SILGEL (Sil Gel 611 of Messrs. Wacker Chemie Burghausen),are known in the art and are used e.g. for sealing copper wire ductsthrough printed circuit boards (see FIG. 2).

The inside diameter of bush 8 is conformed to the outside diameter ofwire 1. When the wire 1 is slipped through the extension 10 filled withSILGEL or the sealing compound, part of the compound is displacedthrough an opening (not shown in FIG. 1) or into a channel (22, in FIG.3) through which the compound has been filled in before. The remainingsticky compound fills the interstices between the slipped-in connectingwire and the openings in the cooling element and in the printed circuitboard, with the result of achieving a high-quality, permanent seal and,thus, protecting against moisture and the ingress of contaminants.

The plug connector, i.e., the connection between the connecting wire 1and the other components of the plug connector, is detachable. When theconnecting wire 1 is withdrawn, the permanently elastic sticky sealingcompound VM which is disposed in the extension 10 will shut off theorifice through which the wire 1 extended. Therefore, the connection tothe printed circuit board 3 remains sealed even after removal of theconnecting wire 1. This is important, for example, in order to preventmoisture from propagating through the openings 12, 13 to the side of thebottom plate 2 on which components are fitted.

FIG. 2 shows application of the plug connector of the present invention.This application concerns a controller 14 for an anti-lock vehicle brakesystem. The controller accommodates in a closed housing a printedcircuit board composed of a carrier plate or cooling element 4′ and abottom plate 2′, and equipped with electronic components 5′, which areconnected to a great number of valve coils by way of connecting wiresshown in dotted lines or by connecting wires 15 shown in broken lines.The orifices of the wires 15 through the cooling element 4′ are moistureproof, and are enclosed by a permanently elastic sticky sealing compoundVM with which the extension 10′ of the plug connector of the presentinvention is also filled.

A hydraulic pump 17 is connected electrically to the controller 14 inthe embodiment of FIG. 2. To this end, pump 17 is equipped with massiveconnecting wires (only one connecting wire 1′ is shown). Pump 17 ismounted onto the housing, and the connecting wire 1′ is inserted throughthe receiving and guiding bush 8′. Portion 18, shown in dotted boundarylines in FIG. 2, comprises the plug connector shown in an enlarged viewin FIG. 1 and explained hereinabove. Sealing compounds, such as SILGEL,are filled in a highly fluid state into the area being sealed, inparticular into the opening or extension 10, 10′ at the end where thewire 1, 1′ exits from the bush 8, 8′.

FIG. 3 shows a schematic representation of an embodiment of the presentinvention wherein the connecting wire 1 which is inserted through areceiving and guiding bush 19 is sealed by the permanently elasticsealing compound VM in the exit area of the bush 19. Bush 19 is used tothis effect and is closed by a pierceable diaphragm 20 at the exit side20 of the bush 19 before the connecting wire 1 is slipped in. Proximatethe exit side, in turn there is provided an extension 21 configured asan open feed channel 22, or a like device, into which the initiallythinly fluid sealing compound VM (as is represented in FIG. 3) is filledduring assembly of the controller. This compound VM is collected in theextension 21 which takes up the permanently elastic sticky compound VMwhen the wire 1 is inserted. Shown in FIG. 3, from the left to theright, are the empty bush 19, pouring in of the sealing compound,introduction of the connecting wire 1 and puncturing the pierceablediaphragm 20 (right-hand illustration). The tip 12 of the wire 1 maythen be connected again to the printed circuit board by way of a plugclamp, soldering bush or a similar element. Sealing of the slipped-inconnecting wire by way of the sealing compound VM is already effected inthe bush 19.

What is claimed is:
 1. A plug connector for producing a moisture-proofelectrical coupling between a massive connecting wire and an electricalcontact or contact element, comprising: a receiving and guiding bushwhich accommodates a connecting wire and terminates into an extensionprovided as a reservoir filled with an elastic, sticky sealing compound;a retaining element external to the reservoir; and a foil or a thin wallof any other type which is closed in the beginning and is adapted to bepierced, wherein the tip of the connecting wire penetrates through thereservoir and through the foil or thin wall when inserted into the bush.2. The plug connector as claimed in claim 1, wherein the retainingelement has the shape of a plug clamp, or a soldering bush whichestablishes the electrical contact between the connecting wire and thecontact element.
 3. The plug connector as claimed in claim 1, whereinthe connecting wire is provided with an insulating casing and extendsthrough the bush, the extension and the pierceable foil up to theretaining element.
 4. The plug connector as claimed in claim 1, furtherincluding at least one of a stripping diaphragm or a stripping funnel isprovided at the exit area or at the transition from the bush to theextension.
 5. The plug connector as claimed in claim 1, wherein theconnector is used for connecting a consumer to a printed circuit boardwhich is mounted on a flat-surface cooling element, wherein the bush isseated on the side of the cooling element and the retaining element onthe side of the printed circuit board, and wherein the connecting wireis passed through openings in the cooling element and in the printedcircuit board.
 6. The plug connector as claimed in claim 1, wherein theextension in which the bush ends is configured as a recess on the exitside of the bush and is filled with the sealing compound through a feedopening or a feed channel.
 7. The plug connector as claimed in claim 1,wherein the extension in which the bush ends is filled with the sealingcompound through the bush.
 8. A plug connector to produce amoisture-proof electrical coupling between a massive connecting wire andan electrical contact or contact element, comprising: a receiving andguiding bush which accommodates the connecting wire and includes anextension on an exit side of the receiving and guiding bush that isprovided as a reservoir filled with an elastic sticky sealing compound;and a pierceable diaphragm such that the connecting wire pierces thediaphragm as it exits the reservoir.
 9. The plug connector as claimed inclaim 8, wherein the extension includes a feed opening for the sealingcompound or is connected to a feed channel.
 10. The plug connector asclaimed in claim 8, further including multiple receiving and guidingbushes, each bush including an extension on the exit side of theintroduced connecting wire, wherein the extension is provided as areservoir for the permanently elastic sticky sealing compound.
 11. Theplug connector as claimed in claim 10, wherein each extension includes afeed opening for the sealing compound or is connected to a feed channel.12. The plug connector as claimed in claim 11, wherein the extensions orfeed openings or feed channels are all interconnected for simultaneouslyfilling a number of extensions.
 13. A plug connector for producing amoisture-proof electrical coupling between a massive connecting wire andan electrical contact or contact element, comprising: a receiving andguiding bush which accommodates insertion of the connecting wire, saidbush projecting outside the contact element to provide locating indiciathereto, said bush including an extension on the exit side thereof thatis provided as a reservoir filled with an elastic sticky sealingcompound; and a pierceable diaphragm that acts as a floor of saidextension for providing an exit to the inserted wire.
 14. The plugconnector as claimed in claim 13, wherein said bush includes a chamferedinsertion opening for receiving the connecting wire.